Ethernet instead twisted pair


Hi every body!

I'm new in openROV and I would like to know why use a twisted pair instead an Cat 5 Ethernet wire as umbilical?

I'm afraid to cut the twisted pair with the sea shell. Nobody had this problem before?

Thanks for your answers.


Hi Camille!

These are my guesses as to why they chose this type of tether:

Cat5 is limited to max 100 m (, the OpenROV tether has been tested to 300 m.

Cat5 has a protective casing that could fill up with air, creating buoyancy problems.

Cat5 is thicker and more stiff, reducing maneuverability and creating a bigger bundle.

The cat5 should be more expensive since it basically is three twisted pairs plus the protective casing.

As for cutting it, yes that would create problems, hopefully you will not hook it under obstacles. If you would cut it you can just shorten it or by a new one. It is surprisingly strong, you can lift the entire ROV in the tether.

I hope that made you less worried. I have barely started driving my ROV so I don't have much tether experience yet. I'll look into tether-spools soon I think.

Happy Diving!


Ok thanks for the reply!

Now I'm going to work for 2 month in Angola, I will finish to build it when I will be back!